Apparatus for gripping a downhole tubular

ABSTRACT

A downhole tubular gripping and suspending apparatus adapted for gripping a downhole tubular and suspending said downhole tubular from said apparatus. The apparatus has a housing ( 2 ) and a bottom opening ( 6 ) for introducing said top end of said tubular into a reception chamber ( 5 ) via said bottom opening ( 6 ). External coupler gripping members ( 20 ) are mounted on said housing ( 2 ) and adapted to grip an exterior of the enlarged diameter part of the coupler Shoulder support members ( 30 ) are mounted on said housing ( 2 ) and adapted to engage under said shoulder ( 103 ) of a tubular top end received in said reception chamber ( 5 ).

FIELD OF THE INVENTION

The present invention relates to an apparatus for gripping a downholetubular for use in an oil and gas drilling system and the like.

BACKGROUND OF THE INVENTION

Drilling methods are known wherein a so-called top drive mechanism isused to rotate the string of drill pipe joints. Such a top drivemechanism comprises a body commonly suspended from a travelling block ofa drilling rig and movable vertically along the well bore axis.

The top drive mechanism furthermore commonly comprises a motor (e.g. anelectric or hydraulic motor) secured to the body and having a rotatableoutput member.

It is know to provide the top drive mechanism with an apparatus forgripping and suspending a downhole tubular. This apparatus is in generalarranged beneath the motor of the top drive and interconnected thereto,so that not only the tubular can be raised and lowered but also a rotarymotion can be imparted to the downhole tubular if desired, e.g. fordrilling operations.

A known apparatus for gripping and suspending a downhole tubularincludes a series of clamping jaws arranged in the housing of theapparatus and adapted to clampingly engage on the exterior of a drillpipe or casing pipe in a region remote from the top end of the pipe.This is done to avoid damage to the threaded top end of the pipe.

In the oil and gas drilling industry it is know to use tubulars whereinthe top end is provided with an enlarged diameter coupler (the “box” asit is generally referred to for drill pipe, whereas the lower end isprovided with a screwthreaded end referred to as the “pin”) or thethreaded end of a casing pipe (which is often not provided with anenlarged diameter coupler).

Other tubulars handled by an apparatus for gripping and suspending asherein described are e.g. well linings.

It is generally known that a significant torque has to be exerted on atubular in drilling operations. The known top drive mechanisms are foundto be unsatisfactory in this regard.

A further issue is the safety of the known top drive mechanisms. Also inthis regard the known mechanisms are found to be unsatisfactory.

OBJECT OF THE INVENTION

An object of the invention is to provide an improved apparatus forgripping and suspending a downhole tubular.

A further object of the invention is to provide an apparatus, whichallows for the transmission of a high torque, without compromising thepart of the tubular gripped by the apparatus.

A further object of the invention is to provide an apparatus, which canbe operated safe and reliable.

SUMMARY OF THE INVENTION

The apparatus of the invention grips the coupler on the outside. Asmentioned before drill pipe joints commonly have such a coupler (thebox) which has a larger outer diameter than the drill pipe section andalso is often made of a different steel and/or hardened, and commonlyprovided with a rugged coarse internal (conical) thread forinterconnecting drill pipes. The gripping of the outside of the couplercan thus be effected with high loads on the coupler, withoutunacceptable damage to the coupler and also the diameter of the grippedsurface is greater than the diameter of the pipe section. Both effectsallow the transmission of a high torque to the drill pipe and a reliablegrip on the coupler.

The apparatus also provides a support engaging the underside of theshoulder of the downhole tubular. This amongst others reliably preventsthe tubular from disengaging from the apparatus and dropping down, e.g.into the well bore. This could e.g. be effective when the grippingmembers loose their grip on the coupler (e.g. the gripping membersand/or the actuating means thereof becoming defective).

It is noted that the “shoulder” may be formed in different waysdepending on the composition of the downhole tubular. One option is thatthe coupler itself, e.g. the lower end, forms the shoulder thereof. Alsoit is known to have drill pipes provided with an “upset” at the upperend thereof, which is commonly obtain by forging the upper end to obtaina section of increasing thickness and with a conical widening otherdiameter towards the upper end of the drill pipes. On top of this“upset” the coupler is then fitted, e.g. welded. In such a drill pipethe upset could provide the “shoulder” under which the shoulder supportof the apparatus engages. This would even provide “drop down protection”of the drill pipe (or drill string of interconnected drill pipes) in theunlikely event that the coupler would become detached from the upset ofthe drill pipe, e.g. due to a defective or damaged weld.

Preferably the apparatus is designed such that upon insertion of thetubular top end into the reception chamber first the one or moreshoulder support members are brought into their active position, thenthe shoulder is brought to bear on the one or more shoulder supportmembers (e.g. by lifting the apparatus with respect to the tubular).Thereafter the gripping members are brought into tight grippingengagement with the coupler.

It is envisaged that the apparatus according to the invention isintegrated in a top drive mechanism, but other applications, e.g. forlifting etc. of downhole tubulars in oil and gas drilling operations andthe like are also feasible.

The invention achieves one or more of the above objectives by providingan apparatus which comprises:

a housing having a reception chamber with at least a bottom opening forintroducing said top end of said tubular into the reception chamber viasaid bottom opening;

external coupler gripping means including:

-   -   one or more coupler gripping members moveable mounted on said        housing and adapted to grip an exterior of the enlarged diameter        part of the coupler of a tubular top end received in said        reception chamber,    -   actuating means that cause movement of said one or more coupler        gripping members between an inactive position, allowing        introduction of said top end of said tubular into said reception        chamber, and an active position, wherein said coupler is gripped        by said coupler gripping members;

shoulder support means including:

-   -   one or more shoulder support members moveable mounted on said        housing and adapted to engage under said shoulder of a tubular        top end received in said reception chamber,    -   actuating means that allow displacement of each shoulder support        member between an inactive position, allowing introduction of        said top end of said tubular into said reception chamber, and an        active position, wherein each shoulder support member engages        under said shoulder.

Further advantageous embodiments of the apparatus are disclosed in theappended claims and the description.

The invention also relates to a top drive mechanism including anapparatus for gripping and suspending a downhole tubular as hereindescribed.

The invention also relates to a drilling rig including such a top drivemechanism, as well as to a drilling method wherein use is made of theapparatus for drilling and suspending a downhole tubular as hereindescribed.

The invention will now be described in more detail referring to thedescription wherein a preferred embodiment is disclosed with referenceto the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows in longitudinal section a preferred embodiment of anapparatus for gripping and suspending a downhole tubular according tothe invention, the left-hand half with the coupler gripping members andshoulder support members in active position and the right-hand half withthese members in inactive position,

FIG. 2 shows on a larger scale the lower part of the apparatus of FIG.1,

FIG. 3 shows a cross section along the line III-III in FIG. 2 with theshoulder support members in active position,

FIG. 4 shows a cross section along the line IV-IV in FIG. 2 with thecoupler gripping members in active position,

FIGS. 5 a-f show in different successive stages the gripping of atubular top end using the apparatus of FIG. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

FIGS. 1 and 2 show a downhole tubular gripping and suspending apparatus1 adapted for gripping a downhole tubular 100 and suspending saiddownhole tubular 100 from said apparatus 1.

The apparatus 1 as depicted is adapted to be integrated into a top drivedrilling mechanism. Here the apparatus 1 has a housing 2 fitted with acentral shaft 3, which central shaft 3 is provided with a connector (notshown) for connecting the central shaft to a motor of a top drivedrilling mechanism.

As is generally known a top drive drilling mechanism is movable up anddown in a drilling rig, e.g. suspended from a travelling block of therig, so that the gripped and suspended tubular, e.g. a string of drillpipes or casing pipes can be raised or lowered (into the well bore). Byits connection to the top drive motor, the housing 2 can be made torotate and thereby the gripped and suspended tubular can also be made torotate, e.g. for effecting rotation of a drill bit or the like connectedto the tubular. Such a rotary top drive mechanism could also be employedfor interconnecting and/or decoupling screwthreaded tubulars.

The tubular 100 here is a common drill pipe, e.g. of a 30 ft length,having a tubular pipe section 101 of essentially uniform diameter and atop end provided with a coupler 102, generally called the box, forinterconnecting tubulars 100. The coupler 102 has an enlarged diameterpart of greater diameter than the pipe section 101. As is common fordrill pipes of this type the top end of said tubular 100 also has anexterior shoulder 103, here a conical shoulder forming the transitionbetween the pipe section exterior and the enlarged diameter part of thecoupler 102.

As can be seen the coupler 102 has a tapering internal screw thread forinterconnecting tubulars.

The housing 2 in general forms a reception chamber 5, here with a bottomopening 6 for introducing said top end of said tubular 100 into thereception chamber 5 via said bottom opening 6.

In the housing 2 external coupler gripping means are arranged forgripping the coupler 102 in such a manner that a tight grip is obtainedand large torsional forces can be transmitted from the motor of the topdrive to the coupler 102 and thus to the tubular 100.

In this embodiment the coupler gripping means include multiple couplergripping members, distributed around the reception chamber for thetubular top end, so as to engage on the coupler at circumferentiallyspaced locations (see also FIG. 4).

The gripping members each are designed here as a clamping jaw 20,slidable along an associated guide 21 of the housing 2. The guides 21each form a guide surface 22 tapering to a reduced diameter in thedirection of the bottom opening 6 so that when the clamping jaws 20advance towards said bottom opening 6 said clamping jaws move into theiractive position and a clamping surface 23 of each clamping jaw gripsenlarged diameter part of the coupler 102. It is clear that such aclamping surface 23 can be of a grip enhancing design, e.g. with aroughened surface or the like.

The apparatus 1 further includes shoulder support means including one ormore shoulder support members 30 moveable mounted on said housing andadapted to engage under said shoulder 103 of a tubular top end 100received in said reception chamber 5.

In the embodiment shown here multiple shoulder support members 30 areprovided, distributed about the reception chamber 5 for the tubular topend, here near the bottom opening 6, so as to engage under the shoulder103 at circumferentially spaced support locations (see also FIG. 3). Inthis example three shoulder support members 30 are used.

In the design shown here each shoulder support member 30 is pivotableabout an associated pivot axis 31, here about a pivot axis in a plane atright angles to the tubular 100 to be supported. In the shown versioneach support member 30 can be moved between a raised inactive position(see right-hand side in FIGS. 1, 2) and a lowered active position (seeleft-hand side in FIGS. 1,2).

Below each of the shoulder support members 30 the housing 2 provides astop 32 for abutment of the shoulder support member 30 in its activeposition, so that the force by the tubular 100 on the shoulder supportis directly transferred to the housing. It is noted that this forcecould be enormous, e.g. several hundreds of tonnes (e.g. over 200tonnes), e.g. due to the weight of the drill string, the force requiredto pull the drill string from a well bore, etc.

In the FIGS. 1 and 2 it can be seen that each pivotable shoulder supportmember 30 is linked to a clamping member 20 located essentially abovethe shoulder support member, here via an associated connector rod 35.

In the design shown each connector rod 35 is pivoted to the supportmember 30 at a distance remote from the associated pivot axis 30 via ahinge 36. The other end of the rod 35 is pivoted to a clamping jaw 20,wherein the pivot axis 37 is guided in an elongated slot 26 of the jaw,extending essentially in the direction of the tubular to be supported.

For actuation of the clamping jaws 20 each jaw 20 is connected by anassociated connecting rod 40 to a common ring member 41 which isslideable with respect to the housing 2. The connecting rods 40 arepivotable connected at both ends thereof.

In this embodiment the apparatus 1 has a spring 50 which is arrangedhere such that the spring urges the clamping jaws to their activeposition. The spring 50 here is common for all clamping jaws 20, but itcan also be envisaged that each jaw 20 is associated with its ownspring. The spring 50 here is arranged around the shaft and here iscapable of exerting a significant force (the diameter of the shaft coulde.g. be 300 mm). The spring here rests at its upper end against ansupport ring 51 fitted on the shaft 3. The lower end of the spring 50acts on the ring member 41 and urges the ring member 41 downwards. Hereintermediate ring members 42, 43 are positioned between the lower springend and the ring member 41.

For compressing the spring 50, that is raising the ring member 41 inthis embodiment, a power actuator, here a hydraulic actuator 70 isprovided.

In this embodiment the actuator 70 also allows for the exertion of adownwards force on the ring member 41 and thus on the clamping jaws 20.

Here the actuator 70 is of annular design having an inner ring wall 71supported by suitable bearings 72 on the shaft 3 (above the spring 50)and an outer wall 73 slidable up and down with respect to the inner wall71. The outer wall 73 is connected by roller bearings 75 to anintermediate ring member 43.

The inner wall 71 is fitted with an annular piston 74 to form a lowerand upper variable hydraulic chamber 76 a, 76 b to which hydraulic fluidcan be supplied by a suitable hydraulic power pack.

As the tubular 100 here is a drill string the central shaft 3 here isprovided with a central fluid channel 80 extending from an upper mouthto a fluid connector device extending in the reception chamber 5, saidfluid connector device being adapted to connect to the tubular 100 so asto establish a fluid connecting between said tubular 100 and saidcentral fluid channel 80, e.g. to feed drilling mud into the tubularduring drilling operations.

In the embodiment shown the fluid connector comprises a tube part 85connected to the housing 2 and in communication with the central fluidchannel 80, said tube part being insertable into the top end of thetubular 100. There is a sealing arrangement provided for establishing afluid seal between said tube part and the tubular top end.

In this embodiment the sealing arrangement includes a sealing ring 86extending around the tube part 85 and slideable with respect to saidtube part along a sliding section thereof, while maintaining a fluidseal between said ring 86 and said tube part 85, said ring 86 beingdimensioned to sealingly engage the top end of the tubular 100.

A spring 87 is provided for urging said sealing ring 86 in sealingengagement with said tubular 100.

Referring to FIGS. 5 a-f it will be shown how a tubular 100 can begripped by the apparatus 1.

In FIG. 5 a only the very top end of the tubular 100 is visible, theapparatus 1 being held above this top end. It can be seen that theclamping jaw 20 has been pulled upwards by means of the hydraulicactuator 70 so that it is in its inactive position. Thereby the shouldersupport member 30 has also been brought in its raised inactive position.

The apparatus 1 is then lowered onto the top end of the tubular 100, sothat the coupler 102 enters the reception chamber 5 via bottom opening6. The front face of the tubular 100 comes to bear against the sealingring 86. (see FIG. 5 b).

Thereafter the hydraulic actuator 70 is operated to allow for expansion(lengthwise) of the spring 50, so that the jaws 20 are lowered alongtheir guides 21. Before the jaws 20 actually clampingly engage on thecoupler 102, the shoulder support members 30 reach their active positionresting now on the stops 31 of the housing 2. (see FIG. 5 c).

Once the shoulder supports 30 have reached their active position theapparatus 1 is lifted with respect to the tubular 100 which causes theshoulder 103 of the tubular 100 to come to firmly bear on the supportmembers 30 (see FIGS. 5 d and e).

It is preferred that only now the hydraulic actuator 70 is operated topress the clamping jaws 20 downward, so that the coupler is tightlygripped by the jaws 20 (see FIG. 5 f).

It will be appreciated that as soon as the shoulder support members 30are in their active position any risk of the tubular 100 falling out ofthe apparatus 1 is avoided. Also the support members 30 hold the coupler102 in its place when the jaws 20 are forced with great force downwardalong the coupler 102 to obtain the tight grip.

A preferred detail of the support members 30 is that in the activeposition the contact surface with the shoulder 30 is located above thepivot axis 31, with the effect that any downward movement of the tubular100 results in a tighter clamping of the shoulder by said supportmembers 30.

The present invention also relates to a downhole tubular gripping andsuspending apparatus adapted for gripping a downhole tubular andsuspending said downhole tubular from said apparatus, said downholetubular having a tubular pipe section of essentially uniform diameterand a top end of said tubular having a coupler for interconnectingtubulars, said top end of said tubular also having an exterior shoulder,

wherein said apparatus comprises:

a housing having a reception chamber with a bottom opening forintroducing said top end of said tubular and a part of the tubular pipesection into the reception chamber via said bottom opening;

external tubular gripping means including:

-   -   a plurality of tubular gripping members mounted on said housing        and adapted to grip the exterior of the tubular pipe section,    -   actuating means that allow displacement of said tubular gripping        members between an inactive position, wherein said top end of        said tubular can be introduced into said reception chamber, and        an active position, wherein said tubular is gripped by said        tubular gripping members;

shoulder support means including:

-   -   one or more shoulder support members mounted on said housing and        adapted to engage beneath said shoulder of a tubular top end        received in said reception chamber,    -   actuating means that allow displacement of said shoulder support        members between an inactive position, wherein said top end of        said tubular can be introduced into said reception chamber, and        an active position, wherein each shoulder support members        engages beneath said shoulder.

1-16. (canceled)
 17. A downhole tubular gripping and suspendingapparatus adapted for gripping a downhole tubular and suspending saiddownhole tubular from said apparatus, said tubular having a tubular pipesection of essentially uniform diameter and a top end of said tubularhaving a coupler for interconnecting tubulars, said coupler having anenlarged diameter part and said top end of said tubular also having anexterior shoulder, wherein said apparatus comprises: a housing having areception chamber with at least a bottom opening for introducing saidtop end of said tubular into the reception chamber via said bottomopening; external coupler gripping means including: one or more couplergripping members moveable mounted on said housing and adapted to grip anexterior of the enlarged diameter part of the coupler of a tubular topend received in said reception chamber, actuating means that causemovement of said one or more coupler gripping members between aninactive position, allowing introduction of said top end of said tubularinto said reception chamber, and an active position, wherein saidcoupler is gripped by said coupler gripping members; shoulder supportmeans including: one or more shoulder support members moveable mountedon said housing and adapted to engage under said shoulder of a tubulartop end received in said reception chamber, actuating means that allowdisplacement of each shoulder support member between an inactiveposition, allowing introduction of said top end of said tubular intosaid reception chamber, and an active position, wherein each shouldersupport member engages under said shoulder.
 18. An apparatus accordingto claim 17, wherein multiple shoulder support members are provided,distributed about the reception chamber for the tubular top end, so asto engage under the shoulder at circumferentially spaced supportlocations.
 19. An apparatus according to claim 17, wherein each shouldersupport member is pivotable about an associated pivot axis between araised inactive position and a lowered active position.
 20. An apparatusaccording to claim 19, wherein the housing provides a stop for abutmentof the shoulder support member in its active position, so that the forceby the tubular on the shoulder support is directly transferred to thehousing.
 21. An apparatus according to claim 17, wherein multiplecoupler gripping members are provided, distributed around the receptionchamber for the tubular top end, so as to engage on the coupler atcircumferentially spaced locations.
 22. An apparatus according to claim17, wherein a coupler gripping member is a clamping jaw, slidable alongan associated guide of the housing.
 23. An apparatus according to claim22, wherein said guide forms a guide surface tapering to a reduceddiameter in the direction of the bottom opening so that when theclamping jaw advances towards said bottom opening said clamping jawmoves into its active position and a clamping surface of said clampingjaw grips the coupler.
 24. An apparatus according to claim 19, whereinthe shoulder support members are each linked via an associated connectorrod to a clamping jaw in order to achieve actuation of the shouldersupport members through actuation of the clamping jaws.
 25. An apparatusaccording to claim 24, wherein the shoulder support members are eachlinked via an associated connector rod to a clamping jaw such that firstthe shoulder support members reach their active position, where afterthe shoulder is brought to bear on these shoulder support members, andthen the clamping jaws are brought into their active position.
 26. Anapparatus according to claim 22, wherein each clamping jaw is connectedby an associated connecting rod to a common ring member which isslideable with respect to the housing.
 27. An apparatus according toclaim 26, wherein a power actuator is provided for the common ringmember to move the common ring member towards a position correspondingto the inactive position of the clamping jaws, and wherein a spring isprovided urging the common member towards a position corresponding tothe active position of the clamping jaws.
 28. An apparatus according toclaim 17, wherein the apparatus includes a central shaft fitted to thehousing, which central shaft is provided with a connector for connectingthe central shaft to a motor of a top drive drilling mechanism.
 29. Anapparatus according to claim 28, wherein the central shaft is providedwith a central fluid channel extending from an upper mouth to a fluidconnector device extending in the reception chamber, said fluidconnector device being adapted to connect to the tubular so as toestablish a fluid connecting between said tubular and said central fluidchannel.
 30. An apparatus according to claim 29, wherein the fluidconnector comprises a tube part connected to the housing and incommunication with the central fluid channel, said tube part beinginsertable into the top end of the tubular, a sealing arrangement beingprovided for establishing a fluid seal between said tube part and thetubular top end.
 31. An apparatus according to claim 30, wherein thesealing arrangement includes a sealing ring extending around the tubepart and slideable with respect to said tube part along a slidingsection thereof, while maintaining a fluid seal between said ring andsaid tube part, said ring being dimensioned to sealingly engage the topend of the tubular.
 32. A downhole tubular gripping and suspendingapparatus adapted for gripping a downhole tubular and suspending saiddownhole tubular from said apparatus, said downhole tubular having atubular pipe section of essentially uniform diameter and a top end ofsaid tubular having a coupler for interconnecting tubulars, said top endof said tubular also having an exterior shoulder, wherein said apparatuscomprises: a housing having a reception chamber with a bottom openingfor introducing said top end of said tubular and a part of the tubularpipe section into the reception chamber via said bottom opening;external tubular gripping means including: a plurality of tubulargripping members mounted on said housing and adapted to grip theexterior of the tubular pipe section, actuating means that allowdisplacement of said tubular gripping members between an inactiveposition, wherein said top end of said tubular can be introduced intosaid reception chamber, and an active position, wherein said tubular isgripped by said tubular gripping members; shoulder support meansincluding: one or more shoulder support members mounted on said housingand adapted to engage beneath said shoulder of a tubular top endreceived in said reception chamber, actuating means that allowdisplacement of said shoulder support members between an inactiveposition, wherein said top end of said tubular can be introduced intosaid reception chamber, and an active position, wherein each shouldersupport members engages beneath said shoulder.
 33. A top drive mechanismincluding a body suspendable in a drilling rig for vertical movement,said top drive mechanism further including a motor having a rotatableoutput member, and further including an apparatus for gripping andsuspending a downhole tubular as in claim 17, said apparatus beingconnected to said body so as to allow the vertical motion of a downholetubular as well as rotary motion of the downhole tubular.
 34. A drillingrig for use in oil and gas drilling including an apparatus for grippingand suspending a downhole tubular as in claim
 17. 35. A method ofdrilling and/or servicing a well bore for oil and/or gas, wherein use ismade of an apparatus for gripping and suspending a downhole tubular asin claim
 17. 36. An apparatus according to claim 22, wherein theshoulder support members are each linked via an associated connector rodto a clamping jaw in order to achieve actuation of the shoulder supportmembers through actuation of the clamping jaws.